Electric switch



.Eune 30, 1953 v. w. LEONARD 2,544,047

ELECTRIC SWITCH Filed. Feb. 25, 1951 inv rwkmw \fmcenii, W. Leofiai d Mia AtQTTYQLLJQ Patented June 30, 1953 ELECTRIC SWITCH Vincent W. Leonard, Saugus, Mass., assignor to General Electric Company, a corporation of New York Application February 23, 1951, Serial No. 212,383

(01. acees) 6 Claims.

My invention relates to electric switch mecha nisms, and more particularly to pivoted. bridging contact arms for effecting electrical connection between spaced apart fixed contact members.

It is a principal object of my invention to provide a new and improved pivoted bridging contact which is composed of a minimum number of parts and adapted for ready assembly and disassembly without special tools.

The invention is particularly applicable to cycle timer contacts of the type which are recurrently actuated by a rotatable or other movable timing device.

My invention itself will be more fully understood and its various objects and advantages further appreciated by referring now to the fo1lowing detailed specification taken in conjunction with the accompanying drawing, in which Fig. l is a front elevational View of a time switch in cluding a contact mechanism embodying my invention; Fig. 2 is a fragmentary cross-sectional side elevation of the switch shown at Fig. 1; Fig. 3 is a side elevational view of my improved switch mechanism in assembled position but removed from its mounting; and Fig. 4 is an ex- Dloded perspective view showing the various parts of my new switch mechanism disassembled.

In carrying out my invention in one form applicable to a cycle timer, I provide a rotatable timing dial having a plurality of contact actuating projections. Mounted adjacent the dial I provide a contact block having at least one pair of spaced apart fixed contacts mounted thereon. On the block I pivotally mount a bridging con tact arm which is disposed as to be actuated by contact actuating projections on the dial. The contact arm is formed as a U-shaped member having short side arms and an elongated bight portion, with a pair of coplanar web sections disposed on the inner sides of the short side arms. Between the web sections, and across the bight of the contact arm, there is disposed a movable bridging contact member having bifurcated ends embracing the web sections. The

bridging contact member is biased against stops the particular embodiment of the invention shown, each contact actuating projection 3a extends radially beyond the outer peripheral surface of the timing dial 8.

For cooperation with the timing dial i there is mounted upon the base 2 a contact block i carrying a plurality of pivoted contact members generally designated as 5, each disposed in the path of movement of at least one of the coin tact actuating key projections 3a. The contact block t is formed of any suitable electric insulating material, such as a molded plastic insulating material, and has mounted thereon a pivot pin 6 disposed in substantially parallel spaced relation with the axis of the timing dial 8. The pivoted contact members 5 are mounted upon the pin it and extend substantially tangentially with respect to the dial l. The contact block t is substantially rectangular and has a lower flat surface parallel to the pin 6 upon which are mounted a plurality of pairs of fixed contact members la, lb, each pair of fixed contact members being spaced apart along the length of the associated contact member 5. The free ends of the pivoted contact members 5 extend into rectangular apertures in a positioning plate 8 mounted upon the contact block 4 at the end opposite the pivot pin 6.

The construction of each movable contact member 5 is best shown at Figs. 1, 3 and 4. Each movabie contact member comprises a U-shaped contact arm 9 having short parallel side portions cc and 9b and elongated in the direction of its bight portion. The side portions 9c and 9b are inturned at their upper ends to provide limiting stops do and dd, respectively. Between the inturned end stops tie and ed, each contact arm ii is form d to provide a pair of coplanar webs 9e and iii, the webs being spaced apart and extending along the inner sides of the side arms so and 9b. The web 9; extends the full distance between the inturned stop 9d and the bight of the contact arm 9, while the web 9e on the pivoted end'of the contact arm terminates short of the bight portion, thereby to provide a lateral slot 9g between the web 9e and the bight porticn of the contact arm itself. Preferably the contact arms a are formed of a molded plastic insulatin material.

Within each movable contact arm 9, and parallel to its bight portion between the short side arms Sic and 5b there is disposed an elongated ridging contact bar it of electric conducting material- The bridging contact bar 10 is slotted, or bifurcated, at its ends to fit slidably over the coplanar webs 9e and 9f. l he depth of the slots in the bridging contact bar H3 is such that when the bar is assembled in position between the webs, as shown at Figs. 1 and 3, only limited longitudinal movement of the bridging bar is permitted. Intermediate its ends, and preferably substantially centrally thereof, each bridging contact bar H] is provided with a seating projection 15a on the side adjacent the contact arm 3, and in alignment therewith the contact arm 9 is provided with a seating recess 91'. A compression spring H is seated in the recess 9k and over the projection in between the contact arm is and bridging bar In, thereby normally to bias the bridging bar l into engagement with the inturned end stop 50 and 9d, as shown at Fig. 3,

in asse'rnblying the contact member 5, the spring ii is placed between the contact arm Fl and the bridging bar it and the bridging bar is slidably positioned over the web 91 at the free end or the contact arm. The other end of the bar is then depressed and moved latorally into the until the other bifurcated end of the bridging bar slides up over the positioning web ta. As a thus assembled unit, the contact member appears as shown at Fig. 3, with both. ends or the bridging bar biased against the stops to and so by the compression spring ll.

As illustrated at Fig. 1, the pivoted contact 5 is so mounted on the pivot pin 6 and so po 'tioned by the plate 8 that in the dropped-out position. of the contact member, that end of the o ing bar it adjacent the pivoted end of the is held under pressure against the fixed con tact the bridging bar lil being held slightly away from the stop so by the pressure of t e fixed contact. The free end of the contact i1 normally positioned by means of the plate ii the bridging bar it is spaced away from the contact 'ia.

contact 9 is provided with a depend g having an inclined cam surface posi tinned in the path oi movement of at least one of the movable actuating projections on the dial i. In passing under the ears i-ih the projecticns the contact members 5 about the pivot and into bridging engagementv with the contacts lb, In operation, when any contact member 5 is moved about its pivot *5 towards the fixed contact is, a limited amount of over-travel of the contact arm 3 is provided mowient the free end of the bridging it along the positioning web 9f.

JJhile bave described only a preferred em bodiiuent oi my invention by way of illustration, many modifications will occur to those skilled in the art and therefore, wish to have it under stood that intend in the app-ended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to securev by Letters Patent oi": the United States is:

l. in timer, a rotatable timing dial ir ving an actuating key carried thereby, a contact bloclr. ounted adjacent said dial having ivot pin '.ed thereon, a contact arm i'orinee' oi insulating material and pivotally mounted at one end upon said pin, said contact arm having a cam surface thereon, stop means engaging the other end of said contact arm normally to hold said cam surface in the path of movement of said actuating key, a bridging contact member resiliently mounted on said contact arm. in substantially parallel spaced relation therewith, and

cycle.

all)

all,

a pair of fixed contact members mounted on said block and positioned to be engaged by opposite ends of said bridging contact member.

2. In a cycle timer, a base, a timing dial rotatably mounted on said base, an actuating key carried by said dial, a contact block mounted on said base radially adjacent said dial and having a pivot pin fixed therein and disposed in parallel spaced relation with the axi of said dial, a pair of fixed contact members mounted on said block and spaced apart along a line substantially perpendicular to said pin, a movable contact arm of insulating material pivotally mounted on said pin in substantially tangential relation with said dial and acent said flXEd contact, said contact arm having a cam surface intermediate the ends thereof on the side adjacent said dial, stop means on said. block engaging the free end of said contact arm and holding said arm normally with said cam surface in the path of movement of said actuating and a bridging contact member loosely mounted at opposite ends of said contact arm ,gement with said fixed contact,

ilin cycle timer, a base, a timing dial rotatably mounted upon said base, an actuating lacy carried by said dial, a contact block mounted ur sai "use radially adjacent said dial and having a ",c. ot pin mounted thereon, said pivot pin being disposed in parallel spaced relation with of dial one surface of said block, a pair of fixed contact members mounted upon blocl: at said surface and spaced apart along a line perpendicular to said pin, a movcontact arm of insulating material pivotally mounted at one end upon said pin and disposed substan' ally tangential relation with said dial i sent fixed contacts, said contact and elongated in the direcrn nt portion with short side arms 5 inturned ends providing limiting stops, a of coplanar webs formed internally of said side arms, a camming projection on said contact arm extending toward said dial, an elongated br dging contact member having bifurcated ends disposed to embrace said web portions and ensaid t ng stops, spring means disposed *een said bridging contact member and said bight portion of contact arm, stop means inounte upon said block and engaging the free t arm to hold said contact th said camrning projection in the path of inov ent oi said actuating key and one end or bridging contact member in engagerent with one or" said fixed contact members.

4. In an electric switch, a contact block formed of electric insulating material, a pivot pin mounted upon said block in parallel spaced relation with one surface of said block, a pair of fixed contact members mounted upon said block at said surface and spaced apart in a direction erpendicular to the axis of said pin, a movable contact arm of electric insulating material U-shaped in the direction of its length and pivotally mounted at one end upon said pin for pivotal movement about the axis of said pin, a bridging contact member disposed across the bight of said contact arm and loosely mounted at its ends upon said arm for engagement with said fixed contact members, stop means limit.- ing' movement of the ends of said contactmember relative to said contact arm, and a compression spring between the center portion of said contactv member and the bight of said contact arm, said pivot pin being positioned to. retain said contact. member in contact with. one. of said fixed contact members at all times.

5. In an electric switch, a contact block formed of electric insulating material, a pivot pin mounted upon said block in parallel spaced relation with one surface of said block, a pair of fixed contact members mounted in said block at said surface and spaced apart in a direction perpendicular to the aXis of said pin, a U-shaped movable contact arm formed of electric insulating material and pivotally mounted at one end upon said pivot pin, said arm being elongated in the direction of its bight and having short side portions in parallel spaced relation at opposite ends thereof, said side portions having inturned outer ends and having coplanar webs extending between said inturned ends of said bight, a movable bridging contact bar slot ted at its ends and positioned with said slotted ends slidably embracing said webs, and spring means disposed between said contact bar and the bight of said contact arm thereby normally to bias said contact bar against said inturned ends.

6. In an electric switch, a contact block formed of electric insulating material, a pivot pin mounted upon said block in parallel spaced relation with one surface of said block, a pair of fixed contact members mounted in said block at said surface and spaced apart in a direction perpendicular to the axis of said pin, a U-shaped movable contact arm formed of electric insulating material and pivotally mounted at one end upon said pivot pin, said arm being elongated in the direction of its bight and having short side portions in parallel spaced relation at opposite ends thereof, said side portions having inturned outer ends and having coplanar webs extending between said inturned ends and said bight, the web at the pivoted end of said contact arm being slotted adjacent said bight, a movable bridging contact bar slotted at its ends and positioned with said slotted ends slidably embracing said webs, spring means disposed between said contact bar and the bight portion of said contact arm substantially centrally of the length of said contact arm thereby normally to bias said contact bar against said inturned ends, and an apertured plate mounted upon said block and fitting over the free end of said contact arm to limit movement of said arm away from said fixed contact, said apertured plate normally holding said contact arm in such position that said bridging contact bar engages the fixed contact nearest said pivot pin under the pressure of said spring means.

VINCENT W. LEoNARb.

References Cited in the file of this patent UNITED STATES PATENTS Number 

